body {
  margin: 0;
  padding: 0;
  font-family: sans-serif;
  min-height: 100vh;
  background: linear-gradient(0deg, #fff 50%, #39c5bb);
}

h1 {
  font-size: 50px;
}

ul.na {
  position: absolute;
  top: 50%;
  left: 28%;
  transform: translate(-50%, -50%);
  margin: 0;
  padding: 0;
  display: flex;
  font-size: 30px;
}

ul {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  margin: 0;
  padding: 0;
  display: flex;
  font-size: 20px;
}

ul li {
  list-style: none;
}

ul li a {
  position: relative;
  display: block;
  padding: 10px 20px;
  margin: 20px 0;
  text-decoration: none;
  text-transform: uppercase;
  color: #262626;
  font-weight: bold;
  transition: 0.5s;
}

ul li a:hover {
  color: #fff;
}

ul li a:before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border-top: 1px solid #000;
  border-bottom: 1px solid #000;
  transform: scaleY(2);
  opacity: 0;
  transition: 0.5s;
  z-index: -1;
}

ul li a:hover:before {
  transform: scaleY(1.2);
  opacity: 1;
}

ul li a:after {
  content: '';
  position: absolute;
  top: 1px;
  left: 0;
  width: 100%;
  height: 100%;
  background: #000;
  transform: scale(0);
  transition: 0.5s;
  z-index: -1;
}

ul li a:hover:after {
  transform: scale(1);
}

h1 {
  text-align: center;
}
